Spinach

Spinach boasts an unusual diversity of growth habit and flower type. While your best seed producers will have both male and female flowers, they may also grow just one or the other.

Nitrate concentration in spinach leaves can reach dangerous levels if an ammonia-based fertilizer is used.

Germination
Sow in full sun or partial shade, 0.5" deep. Spinach seed germinates at temperatures of 55-70° F. Allow 15 days for germination.

Can be sown outdoors in early spring or fall, provided that you expect a mild winter. Thin to six inches apart in rows two feet part, making sure to remove any exceptionally stunted plants as these are most likely males that will not produce seed. After your first thinning, you may find that some of your spinach begin growing flower stalks earlier than others. These more rapid growers are less likely to produce a good seed crop, and may be eaten.

Pollination
Spinach will produce flower stalks only when they have 12.5-15 hours of daylight per day.

Spinach is cross-pollinated by wind.

Seed Collection
    When your pants begin to yellow, the seed can be stripped off by hand. If your seed-stalks are wet from rain, you may want to cut the stalks and bring them inside to dry before collection.